Spiral gearing



Oct. 12, 1937. EBEARE I 91 SPIRAL GEARING 1 Filed July 24, 1935 5Sheets-Sheet 1 Oct. 12, 1937. L. E. BEARE SPIRAL GEARING Filed July 24,1955 5 Sheets-Sheet 2 z a W M flzlorizeg.

- L. E. BEA

Oct. 12, 1937.

SPIRAL GEARING 5 Sheefsr 3 Filed July 24, 1935 .27 b "anion- Ieozza rdffieare,

Oct. 12, '1937'. E. BEARE SPIRAL 'GEARING Filed July 24, 1955 5Sheets-Sheet 5 Patented Oct. 12, 1937 srIRAL GEARING Leonard E. Beare,East Chicago, Ind.

Application July 24, 1935, Serial No. 32,942 V 9 Claims.

and a cooperating external gear adapted to serve as a gear reductiondevice.

One of the primary objects of the invention is to provide anintermeshing internal gearand cooperating external gear which is adaptedto engage the internal gear at diametrically opposed points andeliminate the use of thrust bearings or the like on the external gearshaft.

A further object of the invention is to provide compact pairs of spiralgears whereby power may be transmitted quietly and efficiently atdesired shaft angles and at desired gear ratios up or down butpreferably down. Due to the sliding surface contact of the teeth, theteeth may be of any des'iredcross section. A further object of theinvention is to provide spiral gearing which is adapted for use inrotary pumps for liquids or gases.

Another object of the invention is to provide a rotary pump having buttwo moving parts and is adapted to pump a fluid with a minimum ofturbulence and pulsations. A further object of the invention is toprovide a gear transmission wherein an internal ring gear is providedwith cross threads adapted to make a sliding, rather th'ana rollingdriving connection with an internal 'g'ear.

. I The 'gearingis capable of the use in many dif- 'ferent devic'a'buthas been illustrated in a rotary pump adapted for use in a superchargerfor an internal combustion engine or the like.

The invention is illustrated in a preferred embodiment in theaccompanying drawings in which- Figure 1 is an elevational view showinga rmg gear with cross-slotted teeth in engagement with an external gear,suitable for power transmission and gear reduction; Fig. 2, a brokensectional view of the gearing asshown in Fig. 1; Fig. 3,' a sectionalview of the rotary gear pump taken as indicated at line 3 of Fig. 4;Fig. 4, a sectional view of. the pump taken as indicated at .line ofFig. 3; Fig. 5, an elevational view similar "to Fig. 1 but showing aring gear serving as a rotary .head andapiston-rotortherein; Fig. 6, abroken plan view of the parts shownin Fig. 5; Fig. '7, an *ele vationalView similartoFig; 5, the piston-rotor being removed; Fig. 8, a brokensectional view taken as indicated at '1ine:8-8 of Fig. 7; Fig. 9, an endview of the piston-rotor; Fig. 10, an elevational View of the same; Fig.11, a sectional View taken as indicated at line H of Fig. 9;,Fig. 12, abroken sectional view taken as indicated at line l2-l2 of Fig. 9; Fig.-13, an elevational view of .the assembled pump; and Fig. 14, a brokensectional view of the same taken as indicated at line ill-M of Fig. 13.

In order to understand the invention, we will 5 refer first to thesimple embodiment shown in Figs. 1 and 2 wherein a ring gear I5 iscarried by 'a yoke Iii on a drive shaft H. The gear i5 is providedwithcross slots or threads I8 and I9 which intermesh with the teeth orthreads 20 provided on the external gear 2 l which is mounted on a shaft22. As the gear 2! engages the gear [5 at diametrically opposed points,it is necessary for it to engage the slots H3 at one side and the slots59 on the opposite side. It may be noted that the gears do'not make arolling contact as in the case of ordinary spur gears, but the contactis sliding and accordingly, the teeth may be of any desired length andcross-section such as dove-tails or the like. It will also be understoodthat for the particular combination of spiral angles illustrated whenthe shaft ii is rotated, it will cause the shaft 22 to be rotated atabout a three to one ratio. A more general characterization of theinvention maybe had by a direct comparison with the so-called spiralgearing which in an analogous case would have spiral gears of equaldiameter and spiral angles, mounted externally to each other, so thatthe gears roll over the surfaces of each other in addition to sliding anequivalent distance across the face of the contacting teeth. Thisnecessitates the conventional rolling clearance to prevent the teethfrom interfering and permits but a small area of contact on the teeth.Also, the shafts must lie in parallel planes, which takes additionalspace for the shafts and gears. With the present construction, theshafts may lie in the same plane and the centers of rotation of thegears will be identical. There is a sliding movement'of one set of teethbetween the teeth of the other set but there is no rolling andaccordingly there may -be surface contact to substantially the fulldepth of the teeth. However, if gears of relatively wide radial widthare used, it is not feasible to have the surface contact over the entirelength of the teeth because the ends of such. spherically shaped gearsare rotating in smaller circles than their medial portion. Thisexcessively wide arc -'of contact between the gears gives rise tointerference in the same manner as when there is too great a width ofcontact between an ordinary worm and face of the wormgear.

In the present construction the shafts are also angularl'y disposed anda yoke must be used to rotate the outer gear i5 around the inner gear2|, and the shafts must intersect at some obtuse angle greater than Toprevent the same teeth from contacting through an excessively long areof rotation which would result in a gearing of 1:1 ratio or practicallya splined shaft fitting, the useful shaft angles for this type ofgearing should not approach too closely to Of the many combinations ofspiral angles and gear ratios which are possible for each shaft angle,one of the simplest and most durable has been illustrated. This is thecombination in which the spiral angle of one of the gears, preferablythat of the external gear i5, is equal to the shaft angle, and only theouter gear needs to have cross-threaded spirals.

There are certain combinations. of spiral angles which are undesirableand inoperable; Since the gears have no mechanical advantage and thespeed ratio can only be changed by changing the spiral angle, areduction greater than 3:1, employing an efiective spiral pitch ofroughly 20 is about the limit for efhcient power transmission. For amuch larger reduction, the gear would have to be oifset with respect tothe shaft 22 to prevent interference with it, and the long gaps in theteeth created by cross-threaded spirals at a small angle to each othermakes it difiicult to secure a sufficiently long are of contact with theother gear. Two consecutive spirals of the same right or left-handdirection will not be in contact with the driven gear and the drivewould not be smooth or continuous.

In any combinations in which both gears are cross-threaded at spiralangles closely approaching equality, the above condition will again beapproached and there will be points throughout the rotation in which thearea of contact between the teeth is greatly reduced.

Byproperly enclosing the gear 2i, a certain amount of pumping effect maybe obtained by having a ring gear I5 serve as a rotary valve head. Thedevice may be assembled by having a removable sector as will bedescribed in the embodiment below.

The type of gearing shown in Figs. 1 and 2 may be employed in a rotarypump of the type shown in Figs. 3-14 by elongating certain of the gearteeth and deepening the associated slots and enclosing the assembly in asuitable housing.

Referring particularly to Figs. 5-10, it will be seen that a rotary head23 is provided with internal cross-threads 24 and 25 and a pair ofdeepened cross-ports 23 and 21 to receive the vanes 28 of thepiston-rotor 29 mounted on the shaft 39. If desired, the shaft 38 may beprovided with tapering trunnions 3! to fit Within the gear housingdescribed below. The gear 29 is provided with suitable teeth or threads32 which, when assembled as shown in Figs. 5 and 6, engage slots 24 atone side of the rotary head 23 and slots 25 at the diametrically opposedside. The rotary head 23 is carried by a yoke 33 provided on the drivingshaft 34. In the embodiment illustrated, the gearing is so arranged thatthe head 23 makes three revolutions for one complete revolution of thepiston rotor 29. Thus it will be understood that a vane 28, duringrotation of the two gears, may pass through the port 25 in the head andthe head will make a complete revolution while the same vane makes athird of a revolution and is then ready to pass through the port 21 tothe other side of the rotary head 23. The action of the vanes or pistons28 is the same as that of the teeth 32 except that the parts are longer.This mechanism is housed, as shown in Figs. 3, 4, l3 and 14 by means ofa frame 35 which affords a journal 36 for the shaft 34 and to which apump housing 31 is secured by means of bolts 38. The housing 31 affordsjournals 39 for the trunnions 3| and is equipped with a removable plate49 secured in position by means of screws 4!. The housing is furtherprovided with flange members 42 to partially enclose the deep slots 26and 21 in the rotary head 23. If desired, the flanges 42 may becontinued around the housing so that the slots and head 23 are never,exposed. The housing is further provided on each side with an intakeport 43 and an exhaust port 44. The two intake ports 43 may be connectedtogether, if desired, and likewise the two exhaust ports 44. Theseconnections are not shown although it will be understood that there issufficient room between the flanges 42 and the shaft 38 to permit theconnecting parts to be installed without interfering with the rotatingyoke 33.

In order to facilitate assembly of the device, the gear 29 is providedwith a removable sector 45 which is securely held in position by screws46. Also, the vanes or pistons 28 may be removably secured to the rotorby means of machine screws 4'! as shown in Figs. 9, 11 and 12. Inassembling the device, the vanes 28 and sector 45 are removed from therotor and the cover plate 48 taken off of the housing 31. The openportion of the gear 29 may then straddle the threads 24 and 25 and thehead 23 and gear 29 rotated into mesh. The vanes 28 may then be slippedinto position through one of the ports 43 and secured into position bymeans of the screws 41. In like manner, the other vanes may be insertedand the cover plate 40 replaced.

In operation, the shaft 34 may be used to rotate the head 23, and thehead 23 will present a port or deep slot 26 through which the vane 28may pass and will cause the vane to sweep through the housing from theinlet to the exhaust port. The instant the vane clears the head 23, thechamber between the vane and the head will be sealed off except for theintake port 43. After the vane passes the exhaust port 44, the head willpresent the port 21 to permit the vane to pass back through the headand. commence a pumping operation on the return cycle. All of the vanesoperate in the same manner and the action is very smooth and capable ofhigh speed.

If desired, the driving gears, on a pump of this type, may be placed onthe shafts 30 and 34 outside of the gear housing. Of course, such gearscan be of the spur or beveled type, but it is preferred to use spiralgears inside the housing, as shown.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, but the appended claims should be construed as broadly aspermissible, in view of the prior art.

I claim:

1. A pair of intermeshing gears comprising: an internal gear, and anexternal spur-type gear intermeshing with said internal gear at twodiametrically opposed points thereon.

2. Reduction gearing comprising: an internal spiral ring gear, and anintermeshing spur-like gear therein in driving engagement with saidinternal gear at diametrically opposed points thereon.

4. In combination: an .internal ring gear equipped with slotted crossedteeth; and an external spur-like gear therein having teeth intermeshingwith the ring gear teeth at diametrically opposed positions.

5. A pair of intermeshing reducing gears comprising: an internal spiralring gear having crossed threads; an externally threaded gear havingspur-like teeth dove-tailing with the threads of said ring gear atdiametrically opposed points. l

6. In combination: an internal ring gear provided with crossed spiralthreads of equal spiral angles and opposite hands, and a spur-like geartherein intermeshing with the spiral threads of one hand at one sectorand with those of the opposite hand at a diametrically opposed sector.

'7. In combination: a spiral gear equipped with sets of crossed teeth;and a spur-like gear having teeth intermeshing with each of therespective sets of teeth at diametrically opposite positions.

8. A device as specified in claim 7, in which the centers of rotation ofboth gears are identical, the contacting tooth edges are radialextensions from the center of rotation so that the tooth profiles are'dovetailed in the grooves of the cooperating gear, and the ends of theteeth are spherically concentric with respect to said grooves in thecooperating'gear.

9. A power transmission means comprising: two shafts mounted at obtuseangles in the same plane, means for supporting said shafts, a gearmounted on the intersecting end of one shaft, a second gear mounted onthe second shaft at the point of shaft intersection, and diametricallyopposed toothed driving contact'between the two gears.

LEONARD E. BEARE.

